1. Field of the Invention
The invention relates to a closing device for a container in general and for a cooking pot or steam pressure cooking pot in particular.
2. Description of Related Art
At a time of increasing health awareness, there is also a greater demand for food preparation methods which are advantageous from the point of view of nutrition. At the same time, in a hectic world in which people want to and are able to spend less and less time on everyday household chores, there is a desire for fast and efficient food preparation. Steam pressure cooking pots satisfy these two apparently conflicting requirements outstandingly by permitting rapid and gentle cooking of food.
In principle, steam pressure cooking pots have been known for decades. However, the known steam pressure cooking pots have a number of disadvantages.
From the fifties, for example, and more specifically from patent specification DE 896 409, a steam pressure cooking pot is known with a lid which is closed by means of three jaws gripping round the edge of the lid. A disadvantage of this closure mechanism is that a substantial force is needed for closing it, this force being applied via an unwieldy lever.
More recent developments in the field of steam pressure cooking pots are described in laid-open specifications WO 96/01070, EP-A-1 029 483 and EP-A-1 082 932, for example.
A closure device which is known from laid-open specification WO 96/01070 has a lid with two radially displaceable clamping jaws which are drawn together by a spring mechanism. A disadvantage here is that a seal is prestressed in an undefined manner by pressing vertically on the lid before the clamping jaws are closed. The clamping jaws then slide abruptly inward and cause an annoying noise when they strike the pot edge.
Laid-open specification EP-A-1 082 932 discloses a steam pressure cooking pot with a similar lid as in document WO 96/01070.
U.S. Pat. No. 5,613,424 discloses a control device for opening and closing closure jaws for a pressure pot. The device comprises a control element which is mounted on a lid and, engaging in movement arms, moves radially with respect to the lid.
Furthermore, patent specification CH 254 203 describes a steam pressure cooking pot with an outwardly protruding edge. The lid of the steam pressure cooking pot comprises three gripping members which are bent in a U shape at their ends and which engage under the edge and press the lid with an interposed seal against the top face of the pot edge.
The document FR 2 809 608 A1 discloses a closing and opening device for a lid of a steam pressure cooking pot, which lid has four arms with clamping jaws which are driven by rotation of a control element.
In addition, laid-open specification EP-A-1 029 483 discloses a lid for a pressure pot with four movable clamping jaws which can be moved radially via a crank mechanism. This crank mechanism comprises a large number of movable components, some of them made of plastic. This crank mechanism is therefore complicated and expensive to produce and assemble, is not long-lasting, and is problematic with regard to hygiene requirements.
All of said devices have, however, further serious disadvantages in common.
The devices mentioned are cumbersome, esthetically unappealing, difficult to clean, and have to be produced with small tolerances.